Hydrodesulfurization reactor



P. W. CORNELL ET AL HYDRODESULFURIZATION REACTOR Filed April 26, 1949 W'@Oglwm LES E. CARTR M ATTORNEY Patented ct. 14, 1.952

2,614,033 HYDRODESULFURIZATION REACTOR Paul W. Cornell,

Carter, Canonsburg, Pa., Corporation, Pittsburgh, Pa.,

Pennsylvania Mount Lebanon, and Charles E.

assignors to Gulf Oil a vcorporation of Application April 26, 1949,Serial No. 89,692

(Cl. .Z3-288) 6 Claims.

This invention deals with chemical reactors, and particularly withcatalytic reactors in which the iiuid to be treated, in vapor or liquidphase, is caused to pass through a body of particulate catalyticmaterial under controlled conditions to effect a desired alteration inthe nature of the fluid.

It has been observed that in catalytic operations, particularly thoseinvolving the hydrogenation of very heavy catalytic charge stocks, aportion of the material fed to the catalyst bed is not vaporized, andcertain phenomena occur which are injurious to the catalyst. They areassociated with the deposition of a layer of heavy material on the topof the catalyst bed and this heavy material in remaining thereon for aconsiderable length of time,'destroys or alters the eiciency of thecatalyst for purposes of the reaction. It has been further observed thatthis phenomenon occurs in the common type of reactor which introducesthe charge to a disengaging or plenum chamber for distribution of theincoming material across the catalyst bed. It has also been observedthat this deleterious effect on the catalyst does not extend into thecatalyst bed beyond a relatively short distance, indicating that oncethe heavy portion of the material has attained a high velocity withinthe bed it is converted to desirable products and does not furthereffect injury to the catalyst. Moreover,`

it has been found that catalyst beds requiring regeneration to oxidizethe contaminants deposited on the catalyst are generally associated witha very much higher pressure drop for the regeneration operation than forthe processing operation, when both of these are carried out within thelength of time allowed `by the type of operating cycle normallyemployed.

Another serious problem encountered in conventional catalyst reactorswhen operated in alternating reaction and regeneration phases is thesevere mechanical load imposed on the arrangements employed forsupporting the catalyst bed. These arrangements generally comprise somekind of a grate, grid, or other structure which must be so built as topermit the gases to pass through it and at the same time to withstandthe strains imposed not only by the weight of the catalyst bed but alsoby the pressure drop developed by the gases passing through the bed.Further, the supporting structure is exposed to the high temperaturesdeveloped by the oxidation of the contaminant on the catalystimmediately adjacent thereto and this also imposes a severe strain onthesupporting structure.

It is a principal object of this invention to treatment of fluidmaterials, involving features 2 provide a catalyst reaction chamber ortower in which the rate at which incoming fiuid'material to be treatedis passed through the catalytic material is equalized, so that allportions of` such,v v

catalytic material are substantially equally effective in the treatmentprocess, to provide optimum utilization of the catalytic material.

It is a further important object of the invention to provide such adevice in which the pressure drop encountered across the body ofcatalytic material during vthe regeneration phase will be as low aspossible consistent with economical size of the apparatus. l

Still another object of the invention is to provide a catalytic reactionapparatus whose design simplifies the construction of the supportingar-v4 rangements for the bed of catalytic material, and which reducesthe degree to which such supporting arrangements are subjected to thehigh temperatures involved in the oxidation of the contaminant duringthe regeneration phase, with consequent reduction in deterioration. ofthe supporting structure.

A further object of the invention is to provide a catalytic reactor soarranged that the velocityy of the fiuid material being passed throughthc catalyst bed is at a maximum near the point atv which it enters thebed and is at a minimum at the point where it leaves, to provide a moreeicient utilizationof the catalytic material anda reduced pressuregradient for the regenerating fluid, thereby reducing the cost of theregeneration operation since the off -gases may be recycled without muchcompression.

An additional object of the invention is to provide a catalytic reactorof the above type in,

the general conguration of a vertical tower containing an laxiallylocated perforate entrance, conduit for the vapors or `liquid to betreated. a` generally cylindrical mass or body of catalytic I vmaterialsurrounding said entrance conduit, and a plurality of circumferentiallyspaced perforate outlet conduits around the catalytic body, the

effective cross-sections of the perforate inlet andl outlet conduitsbeing tapered in opposite directions lengthwise of the tower so as tocontrolthe velocity of fluid passing through the catalyst ma@` terialfor the most eifective utilization thereof.

A further object of the invention is to provide a reaction chamber ofthe type described above in which the arrangements for lling andemptying the chamber with granular catalyst or the likev are simplified.

vide an improved apparatus for the catalytic of control of theapplication of the material to be treated, and especially of its rate offlow through different portions of the catalyst, to provide a moreeiective and economical utilization of the catalyst and to reduce thetime required for regeneration of such catalytic material.

A further important object of the invention is to provide an improvedmethod for the catalytic treatment of fluids, which will increase theemciency of utilization of the catalyst and the efficiency of requiredregeneration operations, and will provide additional operatingadvantages which will be pointed out more particularly hereinafter.

'I'he above and other objects and advantages of the invention willbecome more apparent from the following detailed specification of anexemplary embodiment of the invention, taken in connection with theappended drawings, which form a part hereof, and in which Fig. 1 is avertical sectional view of a catalytic reactor' in accordance with theinvention and especially adapted to the hydrodesulfurization ofhydrocarbonsI in the vapor form, and

Fig. 2. is a horizontal sectional view taken on line 2-2 of Fig. l.

Referring now particularly to Fig. l of the drawing, the preferredembodiment of the invention is there illustrated as a reactor'comprisinga shell I0, which is usually formed of steel and constitutes theprincipal housing and struc-v tural support for the apparatus. Thisshell is provided with any desired or known form of refractoryinsulating liner I2 covering' its inner surface. Fluid material, usuallya heated vapor, to be treated in the reactor is admitted via a nozzle I4into a conduit I6 which extends downwardly in a centered axial locationto a point adjacent the bottom of the tower.

' For reasons which will be pointedA out below, thediameter of inletconduit I6 is reduced along its length until at its closed lower end IIit has reached a minimum size. -The space between theouter periphery ofconduit I6 and the refractory lining I 2 therefore defines anannularchamber laadapted to contain a mass or bed of catae lyticmaterial, generally introduced in particulate form, and adapted to thetreatment of vapors conveyed by conduit I6 and allowed to issue into thebed of catalyst material through orifices '20 in the wall of saidconduit.

Inorder to collect the treated vapors after they have passedhorizontallyand radially from the orifices in conduit I6 and and acrossthe bed of'catalyst, there are provided a pluralityL of collection pipesor conduits 22 which arel spaced about the tower as close as possible tothe inner lining I2. The upper endsY of these condits 22`v are closed,and each conditA is provided with a plurality of fluid-admittingorifices 24 spaced along its length.

It will be observed that the diameter of each outlet conduit 22increases from its closedv upper end 'towards its open lower end, thereason for which will be pointed out in detail hereinafter.

Atthe lower end ofthe tower, all of the conduitsY 2'2- arcincommunication with a plenum chambei' 'lallfold 26 deflhed btw' a IVIPLI.plate zrestlngg upon afbody of insulating material'30 vlfliich` is` inturn 'supported by the bottom of shell.

I 0, andan upper plate or tube sheet 32 suitably supported upon thebottom of the shell as by a flanged metallic liner 34. In view of theconsiderable weight of the mass of catalyst material the tower, upperplate 32 is additionally supported by a plurality of spaced-aparttubular members 36 which rest upon the lower plate 28 and are,therefore, in turn supported by the insulating material 30 and the shellIU. The upper surface of upper plate 32 may be protected from directcontact with the heated catalyst material as by a layer of' insulatingmaterial 38, and the lower ends of outlet conduits 22 are preferablyoffset inwardly as at 40 to pass through plate 32 and be sealed theretoby known arrangements which prevent the escape of particles of catalyticmaterial into the chamber 25.

To provide structural rigidity for the central or inlet conduit I6, andto maintain it in its centered position, its lower end I1 may bereceived within a short cylindrical guide Section 42 extending upwardlyfrom a support plate suitably secured as by bolts to the upper plate 32of chamber 2B; this support plate may thus be removed when required forthe renewal of catalyst in the tower.

It has been found that contact beds of catalytic material employed inthe hydroesulfurization process may be expected to shrink in volumebetween 10 and 15 per cent during their operating life. It is apparentthat if excessive shrinkage occurs in an apparatus of the type describedabove, the upper level of the catalytic body might be lowered suicientlyto enable incoming fluids to by-pass the contact bed. To prevent this,the present invention provides a multiplicity of annular baffles 44adjacent the upper end of the tower, and fastened to a central supportvbaille 4I. This central support baille is provided with a number ofopenings 48 extending wholly or partially around its circumference,these openingsl ings. The closures 50 may be fastened in place by anysuitable securing means.

By providing the openings in the central support baille, the catalystcan be introduced into the bailled sections. When shrinkage occurs, thecatalyst falls from the baiiled zones to replace the Volume lost.Suiiicient catalyst will still remain within the bailled zones toprovide enough resistance to flow to keep vapors from skirting the topof the catalyst -bed ,and thus escape untreated. In this manner, theequipment provided solves the shrinkage and by-pass problem which wouldotherwise render the radial flow reactor ineiective.

The operation of filling the tower with catalyst material mayconveniently be carried out by initially inserting in the axial positiona screen or perforated shape approximating the shape of the conduit I6,so that after filling the tower withv catalyst the inlet conduit may beinserted in place without disturbing the bed; alternatively.

the inlet conduit may be made in sections which are vfastened togetherinsuccession from the bot-- tom upwardly during the filling operation.These.

this velocity -deoreasing asthe fluids pass across the catalyst andreaching a minimum at the point at whi-ch the treated fluids pass intothe orifices ofv the outlet conduits 22. The reduction in velocity ofthe fluid at the outlet point is espe-v cially advantageous since theminimum velocity permits a more efficient utilization-of a 'catalystbefore exhaustion, at which pointthe bed is considered to requireregeneration. Treated fluids entering conduits 22 ultimately pass intomanifold 26 and thence out of the reactor via exit conduit 52. The pathof travel and the low linearvelocity in the catalyst bed duringregenerat-ion permit a reactor of this design to accomplish theregeneration with .a far lowerjpressure drop for the regenerating fluidthan .is found with a conventional reactor employing longitudinal nowthrough a bed of any appreciable depth. This decrease in pressure dropthrough the bed during regeneration will also effect a substantialreduction in the costs associated with the regeneration operation, sincethe olf-gases may be recycled without much compression.

The design of the orifices in the inlet and outn let conduits will besuch as to provide the proper distribution through the bed and theproper uid velocity upon entering and leaving it. In a convention-alreactor the catalyst bed support must withstand not only vthe weight ofthejcatalyst bed above it but also the great pressure drop ime parted bythe fluid medium owing through it.v

By passing the nui-ds parallel to the support tray 32 as is done in thisreactor this tray is required to support essentially only the weight ofthe catalyst. The additional stresses imposed by the pressure drop 'aretaken up by the protected shell Il] and, percentagewise, amount to onlya small portion of the total stresses that thev shell withstands. l

The successive variations in diameter of conduits it and 22 areillustrated in the drawing as obtained by the use of tapered sections atspaced points lalong their lengths.' but it will be understood ythatsuch successive reductions can conveniently be obtained by the use ofstandard reducing fittings connecting separate conduit sections ofproper diameter. In the case of the outlet conduits 22 these reducingfittings will preferably be of the offset type in order to maintain theconduits 22 as close as possible to the inner surface of shell liner l2.The'ideal relationship between changes in the diameters of the conduitsIE and 22 is such that the percentage increase in the sum of thecross-sectional areas of the collector conduits 22 across any zone willcorrespond proportionately to the percentage decrease in thecross-section'alarea ofthe inlet conduit l5, across that Zone. Thehydraulic properties of a properly designed conduit it including itsopenings 2o into the bed will be such that the amount of feed introducedinto any section of the bed will be the same as the amount of feedintroduced into any other section of the bed of the same size. It istherefore necessary to provide a conduit of such shape that the linearvelocity of the material remaining in the conduit after a partialwithdrawal will be the same as the linear velocity of the materialbefore that withdrawal was made.V By maintaining.,e constant;velocity'for all material remaining in the conduit.` after successivewithdrawals, the kinetic. energy,` of the stream within the conduitremains es-r sentially constant as will the kinetic energy lossresulting rfrom the change of direction as withdrawals are made into thebed. This prom-etes a uniform rate of withdrawal :along the axis ofthe-rbed.

The actual magnitude within the conduit I6 is determined by economicconsiderations; that is, by the losses in pressureV whichlare determinedto be economically feasible. Theoretically, therefore, the shape of theconduit is independent of the inlet velocity, and that portion of theconduit lying within the connes of the operating catalyst should be ofsuch shape` that the cross-sectional area at any point'will beproportional to the fraction of the remaining conned length of theconduit at that point` Thus, if L represents the length of the conduit'-It within the operating bed of catalyst and-D the diameter of theconduit opening at the entrance, then the cross-sectional diameter vdatany distance Z from the entrance can be found from the formula whereconsistent units* are used throughout;l Thus the diameter of the conduitI6 halfway` down the bed will be about 70.7 per cent of the diameter atthe top of the bed. Practically, how'-t ever, for reasons of conveniencewe prefer-the use of standard pipe reducing sections'which will enablethe ideal curved shape to beapproximated sufficiently closely forpractical purposes.

The above description deals with the specic' may be made by thoseskilled in the art without departing from the spirit of the invention asd'e` fined in the appended claims.

What we claim is: 1. A reactor comprising a cylindrical shell, a

cirumferentially perforated inlet-conduit* the diameter of whichdecreases downvvar'dly"frornA its entrance at the top of said shell,said inlet conduit extending axially within said shell and:Y

terminating in a closed end spaced from the ad-v jacent shell end, aplurality of perforate col'- lecting conduits the diameter *of eachofwhichf decreases upwardly from its exit end in the vlower portion ofsaid shell, said 'collecting conduits ex-v` tending lengthwise ofA saidshell and closely `ad-l jacent its `inner wall, a support structure fortreatment material extending to the inner Wall of the reactor beneaththe end of vsaid inlet con-V duit and formed with spaced openingscommuni#` eating respectively with said collecting conduits, saidsupport structure defining a collecting cha-mber, and an outlet conduitin communication with said chamber. 'v

2. A reaction tower comprising a vertically arranged cylindrical shelladapted to contain a body of treatment material, a perforatedcylindrical inlet conduit extending downwardly and centrally within saidshell, said inlet conduit being of progressively reduced diameter indownward direction, a support structure extending horizontally acrosssaid shell below the lower end of said inlet conduit, said supportstructure being adapted to support said body of treatment materialthereabove and defining with the bottom of the uniform velocityv portionof said shell a. lower, plenum chamber, a plurality of perforatecollecting conduits or progressively increased diameter in downwarddirection communicating with the plenum chamber through said supportstructure and extending upwardly parallel to said inlet conduit, saidcollecting conduits being located closely adjacent the inner surface oisaid shell, and an outlet conduit communicating with said chamber.

3. A reactor comprising a cylindrical shell having its axis vertical, ayperforated inlet conduit extending from the upper end of said shelldownwardly in a centered position through said shell and terminating ina closed end spaced from the bottom of said shell, the cross-sectionalarea of said inlet conduit decreasing lin downward .direction in suchmanner that the linear velocity of iiuid flowing therethrough after itspartial withdrawal through upstream perforations in said conduit will besubstantially the same as the linear velocity of the -fluid before suchwithdrawal, the said conduit defining between itself and the inner wallof saidshell an annular chamber adapted to receive a body of catalystmaterial, perfor-ate collecting conduits for iiuid passing from saidinlet conduit radially through said chamber, said collecting conduitsbeing disposed about the inner periphery of said shell and havingcross-sectional areas which increase in downward direction in suchmanner that the percentage increase in the sum of their cross-sectionalareas across any horizontal zone corresponds substantiallyproportionally to the percentage decrease in the cross-sectional area ofsaid inlet conduit, a partition located below the lower end of saidinlet conduit, said partition delining a collecting manifold in thelower portion of said shell, said collecting conduits opening into saidcollecting manifold through openings in said partition, and a dischargeconduit leading through the lower portion of said shell from thecollecting manifold.

4. The invention in accordance with claim 3,

vand means carried by said partition for receiving and supporting theclosed lower end of said conduit.

5. A reactor comprising a cylindrical shell having itsaxis vertical, aperforated inlet conduit extending from the upper end of said shelldownwardly in a centered position into said shell and terminating in aclosed end spaced from the bottom of said shell, the cross-sectionalarea of said conduit being progressively decreased toward its closedlower end, and dening between itself and the inner wall of said shell anannular chamber adapted to receive a body of catalyst material,perforate collecting conduits for uid passing from said inlet conduitradially through said chamber, said collecting conduits extendingthrough a, transverse partition located below the closed end of saidinlet conduit and upwardly into the annular chamber surrounding saidinlet conduit at locations about the inner periphery of said shell, anannular baille within said shell surrounding the upper end of said inletconduit, said baille having openings therein for the introduction ofcatalyst material into said chamber and having a depending skirt portionadapted to extend into the bed of contained catalyst material,adjustable closure means for said openings, and a discharge conduitleading from the space beneath said transverse partition.

6. A reactor comprising a shell divided internally by a partition intoan upper chamber for contact material and a lower, fluid collectingchamber, a fluid inlet conduit extending into said upper chamber, saidconduit being perforated throughout that portion which extends into thebed of contact material and varying in diameter from its entrance insubstantial accordance with the formula where laterally spacedcollection conduits varying inversely in diameter with respect to thevarying diameter of said inlet conduit, said collection conduitsextending through said transverse partition and opening into the fluidcollecting chamber, the portion of said conduits above said transversepartition being perforated and so shaped that the percentage increase inthe sum of ltheir several cross-sectional areas across any horizontalzone corresponds substantially proportionally to the percentage decreasein the cross-sectional area of the inlet conduit, and a dischargeconduit leading from said iiuid collecting chamber.

PAUL W. CORNELL. CHARLES E. CARTER.

REFERENCES CITED The following references are of vrecord in the ille ofthis patent:

UNITED STATES PATENTS Number Name Date 2,042,469 Joseph June 2, 19362,078,947 Houdry et al May 4, 1937 2,108,069 Lassait Feb. 15, 19382,143,009 Houdry Jan. 10, 1939 2,150,930 Lassait Mar. 21, 1939 2,257,178Martin et al. Sept. 30, 1941 2,261,293 Samans Nov. 4, 1941 2,276,340Pricket et al Mar. 17, 1942 2,315,208 Kinnard Mar. 30, 1943 2,329,847'McCausland Sept. 21, 1943 2,534,209 Reed Dec. 12, 1950 FOREIGN PATENTSNumber Country Date 291,253 1 Great Britain May 3l, 1928 639,081 GermanyNov. 12, 1936

1. A REACTOR COMPRISING A CYLINDRICAL SHELL, A CIRCUMFERENTIALLYPERFORATED INLET CONDUIT THE DIAMETER OF WHICH DECREASES DOWNWARDLY FROMITS ENTRANCE AT THE TOP OF SAID SHELL, SAID INLET CONDUIT EXTENDINGAXIALLY WITHIN SAID SHELL AND TERMINATING IN A CLOSED END SPACED FROMTHE ADJACENT SHELL END, A PLURALITY OF PERFORATE COLLECTING CONDUITS THEDIAMETER OF EACH OF WHICH DECREASES UPWARDLY FROM ITS EXIT END IN THELOWER PORTION OF SAID SHELL, SAID COLLECTING CONDUIT EXTENDINGLENGTHWISE OF SAID SHELL AND CLOSELY ADJACENT ITS INNER WALL, A SUPPORTSTRUCTURE FOR TREATEMENT MATERIAL EXTENDING TO THE INNER WALL OF THEREACTOR BENEATH THE END OF SAID INLET CONDUIT AND FORMED WITH SPACEDOPENINGS COMMUNICATING RESPECTIVELY WITH SAID COLLECTING CONDUITS, SAIDSUPPORT STRUCTURE DEFINING A COLLECTING CHAMBER, AND AN OUTLET CONDUITIN COMMUNICATION WITH SAID CHAMBER.